KR20150071784A - Method for monitoring torque in hybrid elecric vehicle - Google Patents

Abstract

The present invention relates to a method for monitoring the torque in a hybrid electric vehicle. According to an embodiment of the present invention, the method for monitoring the torque in a hybrid electric vehicle comprises the steps of: calculating the output torque of a motor based on the discharging power of a high voltage battery, power consumption of a plurality of electric field loads and motor speed; calculating a first difference value between motor torque command and the calculated output torque of the motor; comparing the first difference value with the first reference value preset; and entering a fail safe mode when the first difference value is greater than the first reference value.

Description

METHOD FOR MONITORING TORQUE IN HYBRID ELECRIC VEHICLE BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a hybrid vehicle, and more particularly, to a method of monitoring a torque of a hybrid vehicle.

As is known, a hybrid electric vehicle uses an internal combustion engine together with a battery power source. That is, the hybrid vehicle uses the power of the internal combustion engine and the power of the motor in an efficient combination.

The hybrid vehicle includes an engine, a motor, an engine clutch for interrupting power between the engine and the motor, a transmission, a differential gear device, a high-voltage battery, an integrated starter & generator for starting the engine or generating power from the engine. ISG), and wheels.

The hybrid vehicle may further include a hybrid control unit (HCU) for controlling the overall operation of the hybrid vehicle, an engine control unit (ECU) for controlling the operation of the engine, a motor controller a motor control unit (MCU), a transmission control unit (TCU) for controlling the operation of the transmission, and a battery control unit (BCU) for controlling and managing the high voltage battery.

The engine controller may be referred to as an engine management system (EMS). The battery controller may be referred to as a battery management system (BMS). The starter generator may be referred to as a hybrid starter & generator (HSG).

The hybrid vehicle may engage or disengage the engine clutch according to acceleration / deceleration will, vehicle speed, state of charge of the battery, or the like depending on the operation of the driver's accelerator pedal and brake pedal, mode); An HEV mode (hybrid electric vehicle mode) in which the rotational force of the engine is used as the main power and the rotational force of the motor is used as the auxiliary power; A regenerative braking mode for recovering braking and inertia energy during braking or inertia of the vehicle through power generation of the motor and charging the high voltage battery; And the like.

When the hybrid vehicle is switched from the EV mode to the HEV mode, the engine clutch is engaged after the engine speed and the motor speed are synchronized, so that the torque fluctuation is not generated during the power transmission process between the engine and the motor, .

In this way, the hybrid vehicle utilizes both the mechanical energy of the engine and the electric energy of the high-voltage battery, utilizes the optimal operating range of the engine and the motor, and recovers energy from the motor during braking.

It is necessary to judge whether the engine follows the engine torque command or the motor follows the motor torque command in order to provide the running of the fail safe mode of the hybrid vehicle. This requires knowing the torque and speed of the engine, and the torque and speed of the motor.

In such a hybrid vehicle, controlling the torque acts as an important factor for improving the drivability, and therefore research on torque control is proceeding.

However, in general, a hybrid vehicle is equipped with an engine speed sensor for measuring the engine speed and a motor speed sensor for measuring the motor speed. However, the torque sensor for measuring the engine torque and the torque sensor for measuring the motor torque are not mounted It is not. Therefore, conventionally, there has been a problem that the engine torque is predicted based on the air and the fuel amount flowing into the engine, and the motor torque is predicted based on the voltage and current input to the motor, and the vehicle is controlled according to the predicted value.

The matters described in the background section are intended to enhance the understanding of the background of the invention and may include matters not previously known to those skilled in the art.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a torque control system, To a torque monitoring method for a hybrid vehicle in which an engine torque map and a motor torque map are corrected by using a value as a learned value.

A torque monitoring method of a hybrid vehicle according to an embodiment of the present invention includes: calculating an output torque of a motor based on a discharge power of a high-voltage battery, a consumption power of a plurality of electric loads, and a motor speed; Calculating a first difference value between a motor torque command and an output torque of the calculated motor; Comparing the first difference value with a first reference value; And entering the fail-safe mode if the first difference value is greater than the first reference value.

The torque monitoring method comprising: storing the first difference value if the first difference value is less than or equal to the first reference value; Computing an average of the first difference value of the stored set number; Comparing an average of the first difference value with a second reference value; And correcting the motor torque command map if the average of the first difference value is greater than the second reference value.

The torque monitoring method may further include correcting the motor torque map if the average of the first difference value is greater than the second reference value.

The torque monitoring method may further include calculating an output torque of the engine based on an output torque of the motor when the average of the first difference value is less than or equal to the second reference value; Calculating a second difference value between the engine torque command and the calculated output torque of the engine; Comparing the second difference value with a third reference value; And entering the fail-safe mode if the second difference value is greater than the third reference value.

Wherein the step of calculating the output torque of the engine includes the steps of causing a motor torque command to follow a negative value of the engine torque command in a state in which the motor and the engine are synchronized; And determining the absolute value of the output torque of the calculated motor as the output torque of the engine when the motor speed and the engine speed converge to a predetermined value.

Wherein the torque monitoring method further comprises: storing the second difference value if the second difference value is less than or equal to the third reference value; Calculating an average of the second difference value of the stored set number; Comparing an average of the second differences with a fourth reference value; And correcting the engine torque command map if the average of the second difference value is greater than the fourth reference value.

The torque monitoring method may further include correcting the engine torque map if the average of the second difference value is greater than the fourth reference value.

The output torque of the motor

의 식으로부터 연산되는 값으로 결정될 수 있다. 여기서, P_Batt는 고전압 배터리의 방전 파워, P_Load는 복수의 전기 부하의 소모 파워, ω_Mot는 모터의 속도, μ_Mot는 모터의 방전효율, 그리고 μ_Inverter는 인버터의 방전효율이다.

As shown in FIG. Where P _Batt is the discharge power of the high voltage battery, P _Load is the power consumption of the plurality of electrical loads, ω _Mot is the speed of the motor, μ _mot is the discharge efficiency of the motor, and μ _inverter is the discharge efficiency of the inverter.

As described above, according to the embodiment of the present invention, the engine torque and the motor torque can be monitored without a separate torque sensor, and the cost can be reduced.

By learning the engine torque and the motor torque, it is possible to precisely control the engine and the motor by correcting the engine torque map and the motor torque map.

1 is a block diagram conceptually showing a configuration of a hybrid vehicle according to an embodiment of the present invention.
2 is a block diagram of a torque monitoring system for a hybrid vehicle according to an embodiment of the present invention.
3 is a flow chart of a method for monitoring the torque of a hybrid vehicle in accordance with an embodiment of the present invention.
4 is a schematic diagram showing the data structure of the memory of Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms.

1 is a block diagram conceptually showing a configuration of a hybrid vehicle according to an embodiment of the present invention.

1, a hybrid vehicle according to an embodiment of the present invention includes an engine 10, a motor 20, an engine clutch 30 for interrupting power between the engine 10 and the motor 20, A differential gear device 50, a high voltage battery 60 and an integrated starter & generator (ISG) 70, which starts up or is generated by the output of the engine 10, Wheel 80 as shown in FIG.

The hybrid vehicle according to the embodiment of the present invention includes a hybrid controller (HCU) 200 for controlling the overall operation of the hybrid vehicle, an engine controller (ECU) 110 for controlling the operation of the engine 10, a motor (TCU) 140 for controlling the operation of the transmission 40 and a battery controller (BCU) for controlling and managing the high-voltage battery 60. The motor controller (MCU) 120 controls the operation of the high- .

Communication between the HCU 200, the ECU 110, the MCU 120, the TCU 140, and the BCU 160 can be realized by a controller area network (CAN).

2 is a block diagram of a torque monitoring system for a hybrid vehicle according to an embodiment of the present invention.

2, a torque monitoring system for a hybrid vehicle according to an embodiment of the present invention calculates an output torque of a motor and / or an output torque of an engine, and calculates respective motor torque commands and / or engine torque commands And to control the travel in the fail-safe mode or to correct the motor torque map and / or the engine torque map.

The torque monitoring system for a hybrid vehicle according to an embodiment of the present invention includes a hybrid controller (HCU) 200, an engine controller (ECU) 110, and a motor controller (MCU) The torque monitoring system includes a battery controller (BCU) 160, a low voltage DC-DC converter (LDC) 170, a full automatic temperature controller (FATC) 180, a pump unit 190, and the like.

The ECU 110 controls the output torque of the engine 10 in accordance with the engine torque command applied from the HCU 200. [ The ECU 110 includes an engine torque map, and the engine torque map stores an engine target torque corresponding to the engine torque command.

The MCU 120 controls the output torque of the motor 20 in accordance with the motor torque command applied from the HCU 200. The MCU 120 includes a motor torque map, and the motor torque map stores the motor target torque corresponding to the motor torque command. The MCU 120 includes an inverter composed of a plurality of power switching elements, and the power switching element can be composed of any one of an insulated gate bipolar transistor (IGBT), a MOSFET, and a transistor.

The BCU 160 detects an output voltage and an output current of the high voltage battery 60 and transmits a signal to the HCU 200.

The LDC 170 converts the DC high voltage supplied from the high voltage battery 60 into a DC low voltage and supplies it as an operating power to a plurality of electric loads using a DC low voltage. The LDC 170 detects an input voltage and an input current of a plurality of electric loads using the DC low voltage and transmits a signal to the HCU 200. The HCU 200 can calculate the consumed power consumed in a plurality of electric loads using the DC low voltage.

The FATC 180 controls the operation of the air conditioner. The FATC 180 detects an input voltage and an input current of the air conditioner and transmits a signal to the HCU 200.

The OPU 190 is connected to the TCU 140 and controls driving of an electric oil pump (EOP) (not shown) according to information on the state of the transmission 40 transmitted from the TCU 140 . The OPU 190 detects the input voltage and the input current of the EOP and transmits a signal to the HCU 200.

2 shows only the LDC 170, the FATC 180, and the OPU 190 as the controller for detecting the consumption power of a plurality of electric loads, but the present invention is not limited thereto.

The HCU 200 controls the output torque of the engine 10 and the output torque of the motor 20 by integrally controlling the plurality of controllers in accordance with the driver's driving request and the vehicle condition, , The HEV mode, and the regenerative braking mode.

The HCU 200 may be implemented with one or more microprocessors operating according to a set program, and the set program may include a series of commands for performing each step included in the torque monitoring method according to an embodiment of the present invention And the like.

However, the scope of protection of the present invention is not limited thereto. Various modifications that are different from the configuration of this embodiment are possible. For example, in the torque monitoring method according to the embodiment of the present invention described below, some of the processes are performed by the HCU 200, some of the processes are executed by the ECU 110, and some of the processes are performed by the MCU 120 .

That is, the ECU 110, the MCU 120, the TCU 140, the BCU 160, the LDC 170, the FATC 180, the OPU 190, and the HCU 200 are separated A single controller may manage and control the operation of all components.

The HCU 200 may include a motor torque calculation unit 210, an engine torque calculation unit 220, a memory 230, and a torque command compensation unit 240.

The motor torque computing unit 210 computes the output torque of the motor 20 based on the discharge power of the high-voltage battery 60 and the consumption power of a plurality of electric loads.

The output torque of the motor 20 may be determined to be a value calculated by the following equation.

Here, P _Batt is discharging power, P _Load is the discharge efficiency, and μ _Inverter the consumption power of the plurality of electrical loads, ω _Mot the motor 20 velocity, μ _Mot is the motor 20 of the high voltage battery 60 is This is the discharge efficiency of the inverter.

The discharge power (P _Batt ) of the high-voltage battery can be calculated by multiplying the output voltage (Vout_batt) of the high-voltage battery by the output current (Iout_batt). The power consumption (P _Load ) of the plurality of electric loads is calculated based on the consumed power (P _LDC ) of the LDC 170 consumed in the plurality of electric loads using the DC low voltage, the consumed power of the FATC 180 consumed in the air conditioner P _FATC ) and the consumption power (PEOP) of the OPU 190 consumed in the EOP.

In this case, the motor torque calculating unit 210 does not calculate the output torque of the motor 20 in the transient state in which the speed of the motor 20 changes in consideration of the accuracy, and if the speed of the motor 20 is maintained for the set time, The output torque of the motor 20 can be calculated.

The engine torque calculating section 220 calculates the output torque of the engine 10 based on the output torque of the motor 20 that has been calculated. The process of calculating the output torque of the engine will be described later with reference to Fig.

The memory 230 includes a first memory 230a, a motor torque command map 230b, a second memory 230c, and an engine torque command map 230d as nonvolatile memories.

The first memory 230a and the second memory 230c will be described later with reference to FIGS. 3 and 4. FIG.

In the motor torque command map 230b, a motor torque command corresponding to the motor target torque is stored. The engine torque command corresponding to the engine target torque is stored in the engine torque command map 230d.

The torque command compensation unit 240 determines whether or not the motor torque command and / or the engine torque command need to be compensated by learning the motor output torque and / or the engine output torque so that the torque command compensation unit 240 generates the motor torque command map 230b and / And corrects the map 230d.

At this time, the torque command compensating unit 240 may correct the motor torque map stored in the MCU 120 and / or the engine torque map stored in the ECU 110.

Hereinafter, a method of monitoring the torque of the hybrid vehicle will be described in detail with reference to FIGS. 3 and 4. FIG.

3 is a flow chart of a method for monitoring the torque of a hybrid vehicle in accordance with an embodiment of the present invention. 4 is a schematic diagram showing the data structure of the memory of Fig.

3, when the BCU 160 transfers the output voltage Vout_batt and the output current Iout_batt of the high voltage battery 60 to the HCU 200, the HCU 200 calculates the discharge power P _batt (S100). The discharge power (P _Batt ) of the high voltage battery can be calculated by multiplying the output voltage (Vout_batt) of the high voltage battery (60) by the output current (Iout_batt).

The HCU 200 calculates the consumed power (P _Load ) of a plurality of electric loads (S110). The power consumption (P _Load ) of the plurality of electric loads is calculated based on the consumed power (P _LDC ) of the LDC 170 consumed in the plurality of electric loads using the DC low voltage, the consumed power of the FATC 180 consumed in the air conditioner P _FATC ) and the consumption power (P _EOP ) of the OPU 190 consumed in the EOP.

The HCU 200 calculates the difference between the discharge power (P _Batt ) of the high voltage battery and the consumption power (P _Load ) of the plurality of electric loads (S120).

Then, the HCU 200 calculates the output torque of the motor 20 (S130). The output torque of the motor (T _{Mot - calc} ) can be determined by a value calculated by the following equation.

Here, P _Batt is discharging power, P _Load is the discharge efficiency, and μ _Inverter the consumption power of the plurality of electrical loads, ω _Mot the motor 20 velocity, μ _Mot is the motor 20 of the high voltage battery 60 is This is the discharge efficiency of the inverter.

The HCU 200 calculates a first difference value T _{Mot_diff} between the motor torque command T _{Mot_com} and the calculated output torque T _{Mot_calc} at step S140.

The HCU 200 compares the first difference value T _{Mot_diff} with the set first reference value T _ref1 (S150). The first reference value T _ref1 may be determined through experimentation with a value that the skilled artisan deems desirable.

If the first difference value T _{Mot_diff} is greater than the first reference value T _ref1 in step S150, the HCU 200 enters the fail-safe mode and controls the travel (S300).

If the first difference value T _{Mot_diff} is less than or equal to the first reference value T _ref1 in step S150, the HCU 200 outputs the motor torque command T _{Mot_com} , the calculated output torque T _{Mot_calc} of the motor, The first difference value T _{Mot_diff} is stored (S160).

As shown in FIG. 4, the first memory 230a includes n cells. In each cell, a motor torque command T _{Mot_com} , an output torque T _{Mot_calc} of the motor, and a first difference value T _{Mot_diff} ) is stored. That is, the i-th cell stores the i-th motor torque command (T _{Mot_com_i} ), the output torque (T _{Mot_calc_i} ) of the i-th computed motor, and the i-th first difference value (T _{Mot_diff_i} ). When the output torque T _{Mot_calc_1} of the new motor is calculated, the output torque T _{Mot_calc_i} of the i-th calculated motor is newly stored as the output torque of the (i + 1) -th calculated motor, and the output torque (T _{Mot_calc_n} ) is deleted. That is, only the output torque of the n most recently calculated motors is always stored in the first memory 230a. The motor torque command and the first difference value are also stored in the same manner.

The HCU 200 calculates an average (T _{Mot_diff_avg} ) of n first difference values (S170).

The HCU 200 compares the average of the first difference values (T _{Mot_diff_avg} ) with the second reference value T _ref2 (S180). The second reference value T _ref2 may be determined through experimentation with a value that a person skilled in the art judges desirable.

If the average of the first difference value T _{Mot_diff_avg} is greater than the second reference value T _ref2 in step S180, the HCU 200 calculates the motor torque command map 230b based on the average of the first difference value T _{Mot_diff_avg} (S190). At this time, the HCU 200 can correct the motor torque map stored in the MCU 120. The MCU 120 can control the motor 20 in accordance with the corrected motor torque map.

Therefore, by learning the output torque of the motor having the characteristic deviation in accordance with the aging of the hybrid vehicle, the motor can be controlled more precisely.

The HCU 200 determines that the motor 20 is normally driven when the average of the first difference values T _{Mot_diff_avg} is less than or equal to the second reference value T _ref2 in step S200, Lt; / RTI >

The HCU 200 can control the engine 20 to be monitored in a state in which the motor 20 and the engine 10 are in a synchronized state (for example, the speed change stage is P stage or N stage and the engine clutch 30 is engaged) The torque command T _{Eng_com} is applied to the ECU 110 (S200). The HCU 200 can monitor the engine torque when it is determined that the hybrid vehicle is not running, that is, when the speed change stage is the P-stage or N-stage, that is, the state does not affect the running even if the learning progresses.

The HCU 200 causes the motor torque command T _{Mot_com} to follow the negative value of the engine torque command T _{Eng_com} (S210). That is, if the absolute value of the motor torque command T _{Mot_com} is increased to the point at which the output torque sum of the engine 10 and the motor 20 becomes zero, the engine speed and the motor speed increase and converge at a constant value .

When the engine speed and the motor speed converge to a predetermined value (S220), the HCU 200 calculates the output torque of the engine (S230). That is, HCU (200) is determined by the absolute value of the output torque (T _{Eng_calc)} of operation of the engine output torque (T _{Mot_calc)} of the motor, the output torque of the motor operation (T _{Mot_calc).}

The HCU 200 calculates a second difference value T _{Eng_diff} between the engine torque command T _{Eng_com} and the calculated output torque T _{Eng_calc} at step S240.

The HCU 200 compares the second difference value T _{Eng_diff} with the set third reference value T _ref3 (S250). The third reference value T _ref3 may be determined through experimentation with a value that the skilled artisan deems desirable.

If the second difference value T _{Eng_diff} is greater than the third reference value T _ref3 in step S250, the HCU 200 enters the fail-safe mode and controls the travel (S300).

If the second difference value T _{Eng_diff} is less than or equal to the third reference value T _ref3 in step S250, the HCU 200 outputs the engine torque command T _{Eng_com} , the calculated output torque T _{Eng_calc} of the engine, The second difference value T _{Eng_diff} is stored (S260).

As shown in FIG. 4, the second memory 230c includes n cells, and each cell is provided with an engine torque command T _{Eng_com} , an output torque T _{Eng_calc} of the calculated engine, and a second difference value T _{Eng_diff} ) is stored. That is, the i-th cell stores the i-th engine torque command (T _{Eng_com_i} ), the output torque of the i-th engine (T _{Eng_calc_i} ), and the i-th second difference value (T _{Eng_diff_i} ). When the output torque T _{Eng_calc_1} of the new engine is calculated, the output torque T _{Eng_calc_i} of the i-th calculated engine is newly stored as the output torque of the (i + 1) th engine, and the output torque (T _{Eng_calc_n} ) is deleted. That is, only the output torque of the n most recent engines is always stored in the second memory 230c. The engine torque command and the second difference value are also stored in the same manner.

The HCU 200 calculates an average (T _{Eng_diff_avg} ) of the n second difference values (S270).

The HCU 200 compares the average of the second differences (T _{Eng - diff - avg} ) with the fourth reference value T _ref4 (S280). The fourth reference value T _ref4 may be determined through experimentation with a value determined by a person skilled in the art to be preferable.

The average of the second difference value in S280 phase (T _{Eng_diff_avg)} is greater than the fourth reference value _{(T ref4), HCU (200} ) is a second average engine torque command map (230d) on the basis of (T _{Eng_diff_avg)} of the difference (S290). At this time, the HCU 200 can correct the engine torque map stored in the ECU 110. [ The ECU 110 can control the engine 10 according to the corrected engine torque map.

Therefore, by learning the output torque of the engine having the characteristic deviation in accordance with the aging of the hybrid vehicle, the engine can be controlled more precisely.

If the average of the second difference values T _{Eng_diff_avg} is less than or equal to the fourth reference value T _ref4 in step S300, the HCU 200 can determine that the engine 10 is normally driven.

As described above, according to the embodiment of the present invention, the engine torque and the motor torque can be monitored without a separate torque sensor, and the cost can be reduced.

By learning the engine torque and the motor torque, it is possible to precisely control the engine and the motor by correcting the engine torque command map and the motor torque command map.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

10: engine 20: motor
30: engine clutch 40: transmission
50: differential gear unit 60: high voltage battery
70: ISG 80: wheel
110: ECU 120: MCU
140: TCU 160: BCU
170: LDC 180: FATC
190: OPU 200: HCU
210: motor torque calculating unit 220: engine torque calculating unit
230: memory 240: torque command compensation unit

Claims (8)

Calculating an output torque of the motor based on the discharge power of the high-voltage battery, the consumed power of the plurality of electric loads, and the motor speed;
Calculating a first difference value between a motor torque command and an output torque of the calculated motor;
Comparing the first difference value with a first reference value; And
Entering the fail-safe mode if the first difference value is greater than the first reference value;
And a torque sensor for detecting a torque of the hybrid vehicle. The method according to claim 1,
Storing the first difference value if the first difference value is less than or equal to the first reference value;
Computing an average of the first difference value of the stored set number;
Comparing an average of the first difference value with a second reference value; And
Correcting the motor torque command map if the average of the first difference value is greater than the second reference value;
Further comprising the steps of: 3. The method of claim 2,
And correcting the motor torque map if the average of the first difference value is greater than the second reference value. 3. The method of claim 2,
Calculating an output torque of the engine based on an output torque of the motor when the average of the first difference value is less than or equal to the second reference value;
Calculating a second difference value between the engine torque command and the calculated output torque of the engine;
Comparing the second difference value with a third reference value; And
Entering the fail-safe mode if the second difference value is greater than the third reference value;
Further comprising the steps of: 5. The method of claim 4,
Wherein the step of calculating the output torque of the engine comprises:
Causing a motor torque command to follow a negative value of the engine torque command while the motor and the engine are synchronized; And
Determining an absolute value of an output torque of the calculated motor as an output torque of the engine when the motor speed and the engine speed converge to a constant value;
And a torque sensor for detecting a torque of the hybrid vehicle. 5. The method of claim 4,
Storing the second difference value if the second difference value is less than or equal to the third reference value;
Calculating an average of the second difference value of the stored set number;
Comparing an average of the second differences with a fourth reference value; And
Correcting the engine torque command map if the average of the second difference value is greater than the fourth reference value;
Further comprising the steps of: The method according to claim 6,
And correcting the engine torque map if the average of the second difference value is greater than the fourth reference value. The method according to claim 1,
The output torque of the motor

Of the torque of the hybrid vehicle is calculated as a value calculated from the following expression.
Where P _Batt is the discharge power of the high voltage battery, P _Load is the power consumption of the plurality of electrical loads, ω _Mot is the speed of the motor, μ _mot is the discharge efficiency of the motor, and μ _inverter is the discharge efficiency of the inverter.

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